generally speaking, i think bitcoin has a role to play in countries where citizens face high taxes, high capital controls or confiscation risk. from that point of view that is interesting. >> you have mentioned china. they have come down pretty hard on bitcoin. >> i think so. 70% of the recent turnover in bitcoin exchange basically involved a cnyb on the other side. this has become an object of speculation in china just like other things, even garlic in china. >> people have made comparisons to tulips. there was a professor in the netherlands who made this comparison just this week. you would say no, don't worry about that it, is not a tulip? >> i think right now add today's level, a,000, you can't say clearly it is a bubble. this is where i would disagree with green span. this piece makes that point dwight well. >> david woo disagreeing with allen greenspan. we will be back in two. >> welcome back to "street smart." we had our fifth down day in the market today. trish, you look at where the market closed, the s&p 500 down a half percent. that means we are now down 1.5% over the past fiv